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Hello:
I send you a function that read RSA public and
private key from a file:
RSA *RecuperaClavesRSA(int type, char
*pemfile)
{
FILE *fp;
RSA *key=NULL;
switch
(type){
case READPUB:
if((fp =
fopen(pemfile,"r")) == NULL)
{
fprintf(stderr,"Error:
Public Key file doesn't
exists.\n");
exit(EXIT_FAILURE);
}
if((key =
PEM_read_RSAPublicKey(fp,NULL,NULL,NULL)) == NULL)
{
fprintf(stderr,"Error:
problems while reading Public
Key.\n");
exit(EXIT_FAILURE);
}
fclose(fp);
printf("RSA size: %d", RSA_size(key));
return
key;
break;
case
READSEC:
if((fp = fopen(pemfile,"r")) == NULL)
{
fprintf(stderr,"Error:
Private Key file doesn't
exists.\n");
exit(EXIT_FAILURE);
}
if((key =
PEM_read_RSAPrivateKey(fp,NULL,NULL,NULL)) == NULL)
{
fprintf(stderr,"Error:
problmes while reading Private Key. %d
%s\n",type,pemfile);
exit(EXIT_FAILURE);
}
fclose(fp);
if(RSA_check_key(key) == -1)
{
fprintf(stderr,"Error:
Problems while reading RSA Private Key in
\
'%s'
file.\n",pemfile);
exit(EXIT_FAILURE);
} else
if(RSA_check_key(key) == 0)
{
fprintf(stderr,"Error: Bad
RSA Private Key readed in '%s'
\
file.\n",pemfile);
exit(EXIT_FAILURE);
}
else
return
key;
break;
}
return
key;
}
If the parameter "type" is "READPUB" it read the
public key from the file "pemfile", and if this parameter is "READSEC", it read
the private key.
Too, this function show RSA size
correctly.
I hope this function solve your
problem.
Regards.
P.D.: Your name remember me a very famous song of
Eric Clapton ... ;-)
----- Original Message -----
Sent: Tuesday, May 10, 2005 3:55 PM
Subject: Re: Loading RSA keys from
file.
Hi Angel,
Thank you for your response. I have changed my code with accordance to
your suggestion but I'm still getting a runtime error when attempting to read
the key from its file.
So far I'm having trouble with 1- reading the key from file, and 2-
RSA_size() , this function generates a runtime error when encountered as well.
I can't think of anything since I'm initializing my RSA object.
Suggestions ?
Angel Martinez Gonzalez <[EMAIL PROTECTED]>
wrote:
Hello Layla:
Maybe, your error disapear if you will change
the following:
apub = PEM_read_RSAPublicKey(f, NULL, NULL, NULL);
Regards.
----- Original Message -----
Sent: Tuesday, May 10, 2005 9:30
AM
Subject: Loading RSA keys from
file.
I'm still not able to load the key from its file and I'm still
encountering an error when I use RSA_size(); a run time error occured
when I try to print the returned size. I'm including a segment of my code
after modification:
************************************************************
RSA *apub;
FILE *f;
seed_prng(); // my function for seeding PRNG
//Allocating apub
apub = RSA_new();
if ( apub == NULL)
//print error mesage
//open key file
f= fopen ("a_rsa_public","r");
if (f == NULL)
//print error message
//Loading key
apub = PEM_read_RSAPublicKey(f, &apub, 0,0); //a run
time error occurs here
if (apub == NULL)
{
// print error message
return -1;
}
/* if I try the following line after the allocation of the RSA object
I get a runtime error as well*/
printf("RSA size: %d", RSA_size(apub);
*******************************************************************************
I'm thankful for any help I can get.
Sebastian
<[EMAIL PROTECTED]> wrote:
Hmm,
take
a look at routines like RSA_new() to create RSA structures. As you coded
'sizeof apub', this will return the size of a _pointer_ - assuming a
32-bit
architecture you will get round about four bytes ;-).
See:
http://www.openssl.org/docs/crypto/RSA_new.html
The
runtime error is caused by calling RSA_size() with a null pointer -
unfortnunfortunately RSA_size() doesn't like null pointers.
See:
http://www.openssl.org/docs/crypto/RSA_size.html
Good
luck,
Sebastian
> Hi all,
>
> I'm trying
to develop a C++ application to encrypt and decrypt data
> using
RSA public key cryptography scheme. I have generated the
>
public/private keys using OpenSSL command line tool. The following C++
> code should read a public key, encrypt data, read private key
and
> decrypt the data:
>
********************************************************************
>
#include
> #include
> #include
> #include
> #include
>
>
> int main()
> {
> char *message ="Hello World!";
> RSA *apub;
> RSA
*aprivate;
> FILE *f;
> int ret;
> unsigned char
*buf;
> unsigned char *e_data;
> unsigned char
*clear_text;
>
>
> //Get key
> f=
fopen("a_rsa_public","rb");
> if(f == NULL)
> {
>
printf("\nError opening public key file");
> return -1;
>
}
> else
> printf("\n Public key file opened");
>
> //load the key
> if ( fread(&apub,sizeof apub,1,f) !=
1)
> {
> printf("\nError reading public key");
>
return -1;
> }
> else
> printf("\nPublic key
read");
>
> //close the key file
> fclose(f);
>
> buf = (unsigned char *) malloc(strlen(message));
>
memcpy(buf,message,strlen(message));
>
> e_data = (unsigned
char *) malloc(RSA_size(apub)); // THIS is where i
> get a run
time error
>
> //encrypt data
>
RSA_public_encrypt(strlen(message),buf, e_data, apub,
>
RSA_PKCS1_OAEP_PADDING);
>
>
//------------------decrypt
> //Get key
> f=
fopen("a_rsa_private","rb");
> if(f == NULL)
> {
>
printf("\nError opening private key file");
> return -1;
>
}
> //load the key
> ret =
fread(&aprivate,sizeof(aprivate),1,f);
> //close the key
file
> fclose(f);
>
> //make sure we loaded
ok
> if(ret != 1)
> {
> printf("\nError reading
private key");
> return -1;
> }
>
> clear_text=
(unsigned char *) malloc(strlen(message));
>
RSA_private_decrypt(strlen((char*)e _data), e_data, clear_text,
>
aprivate, RSA_PKCS1_OAEP_PADDING);
> return 0;
> }
>
>
*******************************************************************************
>
At first I used to get a run time error in the RSA_public_encrypt(...);
> and I figured caused I had e_data initialized as:
>
e_data = (unsigned char *) malloc(strlen(message)*4);
>
>
So instead I used :
> e_data = (unsigned char *)
malloc(RSA_size(apub));
> and now I'm getting a run time as this
line is encountered.
>
> I'm sure someone with experience
would be able to spot my mistake.
>
> I thank you all in
advance for your help.
>
>
>
>
>
> __________________________________________________
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You Yahoo!?
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